Alternative Fuel High Pressure System Small Leak
The AFCM detects a small leak in the high-pressure alternative fuel system based on pressure decay rate after engine shutdown. Common in CNG vehicles where seal aging causes slow gas loss.
Affected components
- Alt fuel high pressure lines
- Alt fuel seals
- Alt fuel tank
Common causes
- High likelihood: Seal aged at fitting or valve
- Medium likelihood: High-pressure fitting loose
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.